Conventionally, there is disclosed a driver assistance device that calculates the position of the sun on the basis of the position of an own-vehicle and the current time, and further calculates the direction in which sunlight enters a driver's seat on the basis of the position of the sun and the travel direction of the own-vehicle (for example, see Patent Literature 1). This driver assistance device can warn in advance that the visibility of the driver in the own-vehicle is reduced by calculating the direction in which the sunlight enters the driver's seat.